Horsepower vs. Torque ?

[Rebel73_imp]

It seems that car and motorcycle people are often obsessed with horsepower, but from what I've gathered, it seems that torque is actually the more important number in the real world.

Horsepower seems to become more important at triple digit speeds, such as in racing, but getting onto freeway on-ramps and 0-60 is more about the torque.

Thoughts?

 

[the Ferret]

Torque makes you move... Horsepower makes you move fast.

 

[gossman_imp]

Torques is why Harleys can be tough for a Hayabusa to beat in the 1/4 mile.

 

[the Ferret]

Any Harley Davidson that gives a Hyabusa a hard time in the quarter also has an abundance of horsepower.

107 ft lbs of torque and 75 horsepower will come off the line easily and quickly but will run out of steam fairly early in the game.

107 pounds of torque and 75 horsepower will haul 2 with luggage effortlessly up to about 90 mph though.

A well balanced bike has both.

 

[Rebel73_imp]

I think torque is more directly correlated with acceleration, and horsepower more with top end speed.

 

[the Ferret]

Rollie Free's Vincent ran 150.313 mph on the Bonneville Salt Flats in 1948 with about 70 horsepower. Just took a long time and a guy foolish enough to wear nothing but a bathing suit to do it lol

Ironically an unrestricted 85 Horsepower CB 1100 will not match that speed on the street since the fastest one reported has gone 134 mph (properly geared it would undoubtedly do it on the Salt Flats). Not much progress in 67 years eh?

 

[Ack-CB11_imp]

I think of it this way. Torque gets you going, HP keeps you going.

 

[Rebel73_imp]

That's part of my point. How often do we really go 100+?
I may flirt with the ton on occasion, but I'll never marry it. Lol.

 

[flynrider]

I've never really understood this discussion. Torque is one of the two measurable components used to derive engine horsepower. The other is RPM, but you never hear anyone comparing horsepower vs. RPM.

An engine that puts out a lot of torque, but doesn't rev very high is power equivalent to an engine the puts out a lower torque value, but revs faster. Gobs of torque at really low RPMs are ideal for things like tractors and military tanks. Tiny amounts of torque spun at really high rpm are good for things like turboprop engines on airplanes. Both of the above engines can have the exact same amount of horsepower, but torque and RPM relationships are quite different, to suit their very different needs.

 

[gossman_imp]

Any Harley Davidson that gives a Hyabusa a hard time in the quarter also has an abundance of horsepower.

107 ft lbs of torque and 75 horsepower will come off the line easily and quickly but will run out of steam fairly early in the game.

107 pounds of torque and 75 horsepower will haul 2 with luggage effortlessly up to about 90 mph though.

A well balanced bike has both.

You are right, I should have said 1/8 mile they will give the Hayabusa a battle.

 

[cbdtran_imp]

I think torque is more directly correlated with acceleration, and horsepower more with top end speed.

torque and horse power are the same - energy generated by the engine. You are on your bicycle in first gear you generate more torque to climb hill. On 6th gear you generate more horse to go fast on downhill. Same you, same energy

 

[Rebel73_imp]

From Carthrottle.com

"Where horsepower determines how fast a vehicle can travel, torque at the wheels determines how quickly that speed can be reached. The greater the torque figure, the faster the acceleration."

http://www.carthrottle.com/post/the-difference-between-torque-and-hp-explained/

The two are closely related, but not exactly the same thing.

 

[the Ferret]

From Carthrottle.com

"Where horsepower determines how fast a vehicle can travel, torque at the wheels determines how quickly that speed can be reached. The greater the torque figure, the faster the acceleration."

http://www.carthrottle.com/post/the-difference-between-torque-and-hp-explained/

The two are closely related, but not exactly the same thing.

LOL I think that's what I said in post 2 :celebrate:

 

[Dakota_imp]

Horsepower does work and is what accelerates the vehicle. Torque is a simple force and can be increased or decreased without a change in horsepower. Torque X speed = horsepower. Neither one is energy.

 

[DBXXX_imp]

Horsepower does work and is what accelerates the vehicle. Torque is a simple force and can be increased or decreased without a change in horsepower. Torque X speed = horsepower. Neither one is energy.

I don't understand why anybody even talks about horsepower. To elaborate a little bit on what Dakota said:

Horsepower = Torque x RPM

If you know the torque curve, then you know the horsepower curve automatically. The confusion between torque and energy is that they share the same unit, the newton-meter (Torque - Wikipedia). Torque is a measure of how much force is transferred to the crank each rotation, so you multiply by how fast the rotations are to get the total power.

 

[the Ferret]

ok I'm no engineer but the new BMW s1000rr makes 83 ft lbs of torque and 193 horsepower

a Harley Davidson electra glide make 95 ft lbs of torque and 76 horsepower

The new Indian Chieftan makes 119 ft lbs of torque no reported hp figures I can find

I'm thinking the Harley will pull more weight as evidenced by it GVWR, but the BMW is going to run a heck of a lot faster through the quarter mile, and regardless of massive torque figures the Indian isn't going to be much quicker through the quarter than the Harley

 

[DBXXX_imp]

The weirdness of comparing these numbers is because they're peak values. A Harley (and maybe an Indian?) hits that peak very early and then tails off. Torque at high RPM generates big peak horsepower. 83 lbs of torque and 193 horsepower on that BMW means the torque keeps going in the high range; you hear people talk about 'pulling in any gear' and that's what they mean.

 

[Lord Popgun]

My question is why do engines make torque in pounds feet and when you are torqueing a bolt its in foot pounds?

 

[NightRider_imp]

My question is why do engines make torque in pounds feet and when you are torqueing a bolt its in foot pounds?

Perhaps one is a measure of resistance and the other a measure of overcoming resistance.

 

[Dakota_imp]

My question is why do engines make torque in pounds feet and when you are torqueing a bolt its in foot pounds?

If I recall correctly, scalar vs vector. From my perspective, both are the product of force and distance.